Estimated Effectiveness of a Primary Cycle of Protein Recombinant Vaccine NVX-CoV2373 Against COVID-19
Authors: Alberto Mateo-Urdiales, Chiara Sacco, Daniele Petrone, Antonino Bella, Flavia Riccardo, Martina Del Manso, Marco Bressi, Andrea Siddu, Silvio Brusaferro, Anna Teresa Palamara, Giovanni Rezza, Patrizio Pezzotti, Massimo Fabiani, Stefano Boros, Fortunato (Paolo) D'Ancona, Corrado Di Benedetto, Antonietta Filia, Maria Cristina Rota, Marco Tallon, Maria Fenicia Vescio, Antonia Petrucci, Michele La Bianca, Anna Domenica Mignuoli, Pietro Buono, Erika Massimiliani, Fabio Barbone, Francesco Vario, Camilla Sticchi, Danilo Cereda, Marco Pompili, Francesco Sforza, Pierpaolo Bertoli, Pier Paolo Benetollo, Chiara Pasqualini, Lucia Cisceglia, Maria Antonietta Palmas, Sebastiano Pollina Addario, Emanuela Balocchini, Anna Tosti, Mauro Ruffier, Filippo Da Re, Serena Battilomo, Valeria Proietti, Camillo Odio, Michele Recine, Innocenza Ruberto, Salvatore Ascione, Massimo Bisogno, Gandolfo Miserendino, Massimiliano Navacchia, Beatrice Del Frate, Emanuela Cau, Diego Baiocchi, Danilo Fusco, Domenico Gallo, Maria Rosa Marchetti, Diego Conforti, Carlo Trentini, Antonino Ruggeri, Concetta Ladalardo, Nehludoff Albano, Marco Corona, Paolo Lombardi, Massimo Iacono, Paolo Bruno Angori, Andrea Belardinelli, Milena Solfiti, Stefano Fioraso, Chiara Poma, Nadia Raccanello
Journal: JAMA Network Open (2023)

Protein recombinant vaccine NVX-CoV2373 (Novavax) against COVID-19 was authorized for its use in adults in late 2021, but evidence on its estimated effectiveness in a general population is lacking.To estimate vaccine effectiveness of a primary cycle with NVX-CoV2373 against SARS-CoV-2 infection and symptomatic COVID-19.Retrospective cohort study linking data from the national vaccination registry and the COVID-19 surveillance system in Italy during a period of Omicron predominance. All adults starting a primary vaccination with NVX-CoV2373 between February 28 and September 4, 2022, were included, with follow-up ending on September 25, 2022. Data were analyzed in February 2023.Partial (1 dose only) vaccination and full vaccination (2 doses) with NVX-CoV-2373.Notified SARS-CoV-2 infection and symptomatic COVID-19. Poisson regression models were used to estimate effectiveness against both outcomes. Adjusted estimated vaccine effectiveness was calculated as (1 - incidence rate ratio) × 100.The study included 20 903 individuals who started the primary cycle during the study period. Median (IQR) age of participants was 52 (39-61) years, 10 794 (51.6%) were female, and 20 592 participants (98.5%) had no factors associated with risk for severe COVID-19. Adjusted estimated vaccine effectiveness against notified SARS-CoV-2 infection in those partially vaccinated with NVX-CoV2373 was 23% (95% CI, 13%-33%) and was 31% (95% CI, 22%-39%) in those fully vaccinated. Estimated vaccine effectiveness against symptomatic COVID-19 was 31% (95% CI, 16%-44%) in those partially vaccinated and 50% (95% CI, 40%-58%) in those fully vaccinated. Estimated effectiveness during the first 4 months after completion of the primary cycle decreased against SARS-CoV-2 infection but remained stable against symptomatic COVID-19.This cohort study found that, in an Omicron-dominant period, protein recombinant vaccine NVX-CoV2373 was associated with protection against SARS-CoV-2 infection and symptomatic COVID-19. The use of this vaccine could remain an important element in reducing the impact of the SARS-CoV-2 pandemic.